COLOMA TOWNSHIP, Mich. (CBS Local) — Authorities in southwestern Michigan are urging residents to be vigilant after razor blades were found inside gas pump handles.

Two razor blades — one rusty and one newer looking — fell from a pump handle Monday night while a customer was filling up at the Speedway gas station in Coloma Township, police said.

No one was hurt, but six more blades were found Tuesday atop the pump, CBS affiliate WSBT reported.

“They may have been there trying to do more, but then maybe someone may have saw them and they ran off. I’m not sure what happened,” Chief Wes Smigielski said.

Police reviewed surveillance video, but were not able to determine when they were placed. There is no suspect information.